﻿/*
 * Copyright 2010 Michael Georgoulopoulos
 * 
 * This file is part of Mordor - Source file comparing program.
 * 
 * Mordor is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * Mordor is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with Mordor.  If not, see <http://www.gnu.org/licenses/>.
 * 
 * Contact: info@convexgames.com
 * Website: http://www.convexgames.com
 */

using System;
using System.Collections;

using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;

namespace Mordor
{
    public class ListViewColumnSorter : IComparer
    {
        /// <summary>
        /// Specifies the column to be sorted
        /// </summary>
        private int ColumnToSort;
        /// <summary>
        /// Specifies the order in which to sort (i.e. 'Ascending').
        /// </summary>
        private SortOrder OrderOfSort;
        /// <summary>
        /// Case insensitive comparer object
        /// </summary>
        private CaseInsensitiveComparer ObjectCompare;

        /// <summary>
        /// Class constructor.  Initializes various elements
        /// </summary>
        public ListViewColumnSorter()
        {
            // Initialize the column to '0'
            ColumnToSort = 0;

            // Initialize the sort order to 'none'
            OrderOfSort = SortOrder.None;

            // Initialize the CaseInsensitiveComparer object
            ObjectCompare = new CaseInsensitiveComparer();
        }

        /// <summary>
        /// This method is inherited from the IComparer interface.  It compares the two objects passed using a case insensitive comparison.
        /// </summary>
        /// <param name="x">First object to be compared</param>
        /// <param name="y">Second object to be compared</param>
        /// <returns>The result of the comparison. "0" if equal, negative if 'x' is less than 'y' and positive if 'x' is greater than 'y'</returns>
        public int Compare(object x, object y)
        {
            int compareResult = 0;
            ListViewItem listviewX, listviewY;

            // Cast the objects to be compared to ListViewItem objects
            listviewX = (ListViewItem)x;
            listviewY = (ListViewItem)y;

            // Compare the two items
            if (ColumnToSort == 0 || ColumnToSort == 1)
            {
                compareResult = ObjectCompare.Compare(listviewX.SubItems[ColumnToSort].Text, listviewY.SubItems[ColumnToSort].Text);

                // Calculate correct return value based on object comparison
                if (OrderOfSort == SortOrder.Ascending)
                {
                    // Ascending sort is selected, return normal result of compare operation
                    return compareResult;
                }
                else if (OrderOfSort == SortOrder.Descending)
                {
                    // Descending sort is selected, return negative result of compare operation
                    return (-compareResult);
                }
                else
                {
                    // Return '0' to indicate they are equal
                    return 0;
                }
            }
            else
            {
                float lvi1Int = ParseListItemString(listviewX.SubItems[ColumnToSort].ToString());
                float lvi2Int = ParseListItemString(listviewY.SubItems[ColumnToSort].ToString());

                if (OrderOfSort == SortOrder.Ascending)
                {
                    if (lvi1Int < lvi2Int)
                        return -1;
                    else if (lvi1Int == lvi2Int)
                        return 0;

                    return 1;
                }
                else if (OrderOfSort == SortOrder.Descending)
                {
                    // Return the opposites for descending
                    if (lvi1Int > lvi2Int)
                        return -1;
                    else if (lvi1Int == lvi2Int)
                        return 0;

                    return 1;
                }
                else
                {
                    return 0;
                }
            }
        }

        private float ParseListItemString(string x)
        {
            //ListViewItems are returned like this: "ListViewSubItem: {19}"
            int counter = 0;
            for (int i = x.Length - 1; i >= 0; i--, counter++)
            {
                if (x[i] == '{')
                    break;
            }

            return float.Parse(x.Substring(x.Length - counter, counter - 1));
        }


        /// <summary>
        /// Gets or sets the number of the column to which to apply the sorting operation (Defaults to '0').
        /// </summary>
        public int SortColumn
        {
            set
            {
                ColumnToSort = value;
            }
            get
            {
                return ColumnToSort;
            }
        }

        /// <summary>
        /// Gets or sets the order of sorting to apply (for example, 'Ascending' or 'Descending').
        /// </summary>
        public SortOrder Order
        {
            set
            {
                OrderOfSort = value;
            }
            get
            {
                return OrderOfSort;
            }
        }

    }

}
